The present invention relates to securement devices for a watch strap on a watch casing, in particular a metallic or non-metallic watch strap, of leather or rubber for example.
There are known devices for the securement of a watch strap on a watch casing, for example from WO 98/21630; WO 99/36838 and CH 614,589. WO 98/21630 discloses a bracelet conventionally fixed on an intermediate element which is itself received between the lugs of the watch casing and is fixed to the latter with the help of a pin. Despite the presence of the intermediate element, the mounting and unmounting of the watch strap requires use of a tool to withdraw or push back the pin connecting it to the lugs of the casing.
The drawback of such a securement arises from the need to have recourse to a tool for changing the watch strap and also because the securement pin of the watch strap on the intermediate element as well as the pin fixing this intermediate element on the lugs of the watch casing, remain visible and detract from the appearance of the timepiece.
WO 99/36838 discloses a device for rapid securement without a tool, of a watch strap on a watch casing. This device comprises a first intermediate element mounted on the watch casing and that can slide or turn relative to this watch casing. A second intermediate element to which is fixed the watch strap, can engage the first intermediate element when the latter is in a mounting position relative to the watch casing. In normal service position of this first intermediate element relative to the watch casing, the second intermediate element is locked in a position coupled to the first intermediate element.
This embodiment is complicated, is not easily adaptable to secure metallic watch straps and does not prevent accidental uncoupling of the first and second intermediate elements.
The third document, Swiss patent CH 614,589, discloses a watch casing whose lugs are provided with hinges, having a longitudinal recess open at the end and on the internal surface of the hinge. The bracelet is fixed to a transverse bar whose cross section has the shape of a truncated cylinder permitting in a predetermined angular position to be introduced into the recess of the hinge of the watch casing. For all the other angular positions of this bar relative to the hinge, this bar is trapped in the hinge. Here again, the watch strap can inadvertently separate from the watch casing.
The object of the present invention is to permit rapid and reliable securement without a tool, of a watch strap of any type on a watch casing, whilst avoiding accidental and untimely separation of the watch strap from the watch. It is also an object of the present invention to provide a securement device for a watch strap on a watch casing, which has no visible element or mechanism and which does not detract from the appearance of the piece.
Another object is to permit the sale of all types of bracelets alone, in the form of accessories, which the user can simply mount himself on the watch casing without a tool, which will avoid any inadvertent separation.
The present invention has for its object a device for securement of a watch strap on a watch casing comprising the characteristics set forth in claim 1.